System and method for recording digital data on glass master recording disks

Abstract

A system concept and the components integrated therein for storing useful and control information as well as feature items, general components for data flow control of all components integrated in the system concept as well as special components for data flow and process control of interface systems for laser-beam recorders permit handling of useful and control information as well as feature items independently of physical music/data carriers within premastering and the production of glass masters (mastering) in CD plants. All the various types of information are stored in on-line compatible mass storages and automatically transferred into the sectors calling for the information concerned by general data flow control components. Requests for information can be generated manually or automatically. The time needed to transfer to the requesting sectors or machines is shortened, the premastering expense reduced, the mastering actions automated with the aid of special control components and considerably speeded up as compared to conventional methods by using a network as the carrier medium.

Description

1. Field of the InventionThe invention relates to prestage processes necessary in state of the art production of glass masters for compact disk replication.2. Description of the Prior ArtCurrently, the useful information made available to CD manufacturers for the purpose of replication is furnished on a plurality of greatly differing music / data carriers, each having highly specific features, depending on the existing infrastructure of the client placing the order and the nature of the information concerned. In this respect the type of music / data carrier selected decisively influences both the time and depth needed for processing in the CD plant. At this time the following music / data carriers are of significance throughout the branch:PremasteringDepending on the nature on the music / data carrier furnished, its mechanical / physical quality as well as the structure of the useful information, various steps in processing prior to mastering, i.e. premastering are required of the CD manufact...

AI Technical Summary

Benefits of technology

Even when employing transfer media having a comparitively high read/write speed within the bandwidth of music/data carriers as usual in the branch (CDWO, MO disks, exabyte tapes) the data rates of approx. 3.5 Mbit/sec. currently achievable are low compared to the technical/physical possibilities of the laser-beam recorders used (approx. 25 Mbit/sec.). Transfer media such as exabyte or CD drives thus make use of only a fraction of the existing performance capabilities of laser-beam recorders.

To amortisize the high investment and operating costs of laser-beam recorders which bear no comparison to those of music/data carrier drives CD plants wish to make full use of the performance capabilities of existing laser-beam recorders. Since every non-correctable error inevitably results in having to repeat the complete procedure (a factor taking up a lot of time and money due to the steps involved as described) non-correctable errors in readers and transfer media, operating errors by personnel as well as non-correctable bit errors in transmission need to be avoided. Although the built-in safety mechanisms in CDWO, MOD disk or exabyte tapes achieve higher data rates and more reliable transfer as compared to other music/data carriers usual in the branch they are stressed to the limits of their performance capabilities. Since a substantial safety mechanism consists in re-reading fault positions, the peak data rate of the reader needs to be substantial higher in assuring a continuous minimum data stream than that required on an average. It is only by this asynchronous fast reading, re-reading in case of an error and buffering part of the data stream that a relatively high operating reliability is assured. Since, however, the probability of a reading error occurring increases with the speed of the reading procedure out of all proportion, a compromise is made between process stability and speed in the case of systems usually employed for readers nowdays in mastering. For the above reasons process stability has absolute priority over rapidity.

All current procedures for transferring useful information to the glass master are carried out with the aid of so-called physical transfer media. Ensuring that transfer media is available in time, that the tasks to be done are correctly sequenced as compared to the work specifications, that the transfer media is properly inserted in the corresponding readers and starti

Problems solved by technology

Due to the high demands on the cleanliness of the materials used, the tight tolerances on thickness of the light-sensitive coating and the necessary stability in processing, this procedure is highly time and hardware intensive.

Due to the non-reversibility of this transfer action uncorrected reader errors, interruptions in the data stream to the laser-beam recorder or errors in transfer in the laser-beam recorder result in a glass master which is useless for further steps in processing.

Once an error has been written onto the glass master, caused by non-correctable bit errors or by an interruption in the data stream, no correction is possible in the same working procedure.

II) Disadvantages of Prior Art

Since every non-correctable error inevitably results in having to repeat the complete procedure (a factor taking up a lot of time and money due to the steps involved as described) non-correctable errors in readers and transfer media, operating errors by personnel as well as non-correctable bit errors in transmission need to be avoided.

Since, however, the probability of a reading error occurring increases with the speed of the reading procedure out of all proportion, a compromise is made between process stability and speed i

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